Mitsunori Koike began work as a stone sculptor in Matsumoto, Japan in 1971. His early years were spent in Burlington, Vermont and Carrara, Italy, after which he traveled extensively in Europe to participate in large scale group projects such as the Lindabrunn sculpture symposium in Lindabrunn, Austria.

Since 1984, Koike has worked at Hannoki Studio in Hara Village, Japan. His monuments and sculptures in granite and other stone are found in schools, gardens, hospitals, corporations and government offices throughout Japan.

Koike devotes much of his time to organizing public art events like the Environmental Forum's "Stone and Human" open-air exhibition in the Nagano Exposition in 1992. In 1996, Koike initiated the organization of Fukashi Gallery, a noncommercial gallery in Matsumoto, Japan which specializes in stone sculpture and public art planning.

Koike worked as a resident artist at the Carving Studio in West Rutland in 1993 and 2001. He is an active member of the sculpture symposium community, and has recently participated in symposia in Canada, Lebanon, and the United Arab Emirates.